Continuous process of making carbureted water gas



Dec. 14, 1943. R. M. cHA'rTERToN ETAL 2,336,455 I CONTINUOUS PROCESS OF MAKING CARBURETED WATER GAS Filed April 29, `1940 by-products are also produced Patented Dec. 14, 1943 UNITED STATES PATENT-OFFICE CoNrmUoUs'PaocEss oF MAKmG CARBURETED WATER GAS Rollin M. Chatterton, Malden, and Peter F. Paffen, Cambridge, Mass., asslgnors to Fuel Re- Search Development Corporation, Boston, Mass., a corporation of Massachusetts Application April 29, 1940, Serial N0.1332,154 9 claims. (ci. 1s-205) of gas made by either of these processes. But by the use of our invention, as hereafter described, by-products of much increased value and importance are produced. and the' by-product credits are-so increased that the net production cost of commercial gas is substantially lowered.

It is the general object of our invention to provide an improved process by which carbureted water gas having the usual commercial heating value'may be continuously produced from lowgrade hydrocarbon oil and steam.r

A further object of our invention is 'to provide an improved process for continuously making carbureted water gas, by which process valuable and rendered commercially available.

We also provide an improved process for the continuous manufacture of carbureted water gas, .in which the operating conditions and the resultant reactions can be 'effectively controlled and uniformly maintained. Apparatus suitable for the carrying out of our improved process is shown in thedrawing, which is a front elevation, partly in section, of an externally heated retort and associated mechanism suitable for use inpracticing our invention. Referring to the drawing, We have shown an elongated vertical retort 10, the internal cross section of which gradually increases downward topermit easy and continuous" downward movement of materials charged thereto. The retort l may bemade of a heat-resistant metal or of any suitable refractory or heat-resistant material, and is mounted in spaced relation within a heating chamber i2, commonly made of fire-A brick and provided with an outer metal casing I4.

The furnace I2 is preferably provided with a series of horizontal partitions l5 by whichthe annular space between the zetort l0 and the furnace I2 is divided into a series of combustion spaces 20in which heat isl provided by circula!- tion of externally produced hot combustion gases, Lor by burning producer gas or any other suitable and available gas, andin each case with separate control ofthe heat conditions in. each combustion space 20. y

For illustrative purposes, a gas feed pipe 50 is shown, having branch connections 5l to each combustion space, and each connection being controlled by a valve 52. An air supply pipe 53 vis also shown, which pipe is connected'through branch pipes 54 and valves 55 to the separate combustion spaces. In this way, the gas and air rsupply in each space ,20 may be separately and accurately controlled and a desired temperature uniformly maintained. Any low-grade fuel gas or hot combustion gases may be supplied through the pipe 5|).k

The retort l0 is filled with a suitable fragmentary solid material'M, such as calcined clay,

broken iire-brick or coke, which material is carefully sized and is substantially refractoryandl heat-resistant under the conditions of opera'-I tion. This material M may be supplied from a hopper' 25 through a pipe 26 and chargingdevice 21. At the lower end of the retort, the material M is delivered to a. receptacle 30 by a discharging device 3I, and may be removed therefrom througha spout 32 at such intervals-as may be desired.

Suitable actuating mechanism (not shown) is provided for the charging device 21 and the discharging device 3I, and these devices are preferably operated in predetermined speed relation,- so that afslow but continuous downward Vmovement of the material M in the retort l0 will take place, While at the same time the retort I0 will be continuously aintained substantially full `of the charged ma rial. J

Anoil feed/pipe 3-4 projects downward into the upper part of the retort I0 and is provided with a control valve 35 and preferably also with anoil preheater 36. A discharge'pipe 31 is connected to the upper end of the retort I0.

The gasesiand oil vapors produced in theretort |10 are removed through the pipe 3'I to a .fractionatingcolumn 38, which in turn may be connected with any suitable mechanism for separating the liquid and gaseous products and for condensing the various liquid products ordistillates.

A pipe 40 with a valve 4 l vis provided for introducing steam into the discharge receptacle 30 toable for thecarrying out of .our improved process, we will'now describe .theoperation and advantages of our invention in the manufacture of carbureted water gas and associated by-products.

'I'he retort I0 is first filled with fragmentary solid refractory or heat-resistant material M, and the retort is heated by the circulation or production of hot gases in the combustion spaces 20, suitable provision being indicated at 41 for removal of the waste gases.

When the material M in the retort I has been heated to a desired temperature, oil is introduced through the pipe 34, which pipe projects downward into the retort in the cooler upper portion thereof. This oil may be preliminarilyheated in the preheater 36, which increases the amount o f oil which can be vaporized and cracked in a given time. As the oil leaves the pipe 34, it trickles downward over the heated refractory material M and absorbs heat from the`material over which it flows. Vaporizing and cracking of the oil then takes place, commonly with the deposit of a substantial amount of oil carbon on the material M.

When the apparatus is in continuous operation, the temperature in the oil cracking zone ately controlled combustion chambers permits 'the temperature to be effectively maintained at a desired pointin each different portion of the retort,

The refractory material discharged to the receptacle 30 is still highly heated and contains more or less deposited carbon. Steam is admitted through the pipe 40 to the receptacle 30 to v cool the discharged vmaterial and to conserve heat, and also to prevent the carbon deposited on the material from taking nre and being immediately consumed on exposure to air.

The injected steam becomes highly heated by the heat absorbed from the discharged material, and this hot steam then passes directly upward into the retort, where it com'es in contact with the descending material M and deposited carbon in the water gas zone and supplies a part of the heat required for the water gas reaction.

Conditions are thus extremely favorable for producing water gas, and such gas is produced in substantial quantities by the reaction of the highly heated steam on the deposited oil carbon. This carbon which is deposited on the material M is in a .finely divided state and is highly reactive.

As the highly heatedwater gas travels upwar in the retort, it supplies additional heat to vaporize and crack the oil which has flowed down over the refractory material in the oil cracking zone. 'I'he oil vapors are cracked in the upper part of the vretort under such conditions that substantial.

quantities of liquid by-products are produced which are relatively more valuablethan the oil fed to the cracking zone of the retort, together with oil gas in sumclent amount to enrich the water gas to the required thermal standard for -commercial distribution.

If the cooling of the discharged material in the receptacle I0 does not provide suillcient highly heated steam for the water gas reaction, addiour improved process. The provision of separ- -tory material to the receptacle 30.

tional hot steam may be introduced through the pipe N.

An outstanding feature of our improved process is the ease and accuracy with which temperature conditions can be controlled, and the uniformity with which they may be maintained 'in all partsof the apparatus. As a result of maintaining uniform `temperature conditions, we are able to produce uniform, by-products having predetermined and desired properties.

Our improved process thus has a very important advantage over all intermittent processes in which wide fluctuations in retort temperatures are unavoidable, and in which these variations recur during each cycle of the process.

A5 the oil is discharged from the pipe 34 and -descends overthe filling material, a comparatively cool core is formed along the axis of the retort, which extends downward a greater or less distance. The Alength of this cool core is determined in part by the rate at which oil is fed to the retort and should not extend too far down, or unvaporized oil will be discharged into the receptacle 30.

of the oil vapors are extremely favorable.

Any oil carbon freed by thecracking operation and -deposited on the material M passes downward therewith and is partially'consumed in the water gas reaction. AAny excess carbon not used in this reaction is discharged with the refrac- When removed therefrom, the carbon may be separated from the refractory material by screening and is then available for boiler fuel, while the refractory material itself may b e returned to the hopper 25 for further use in the retortv I0.

The cracking of the oil vapors -under the described conditions, with the retort substantially at atmospheric pressure, results in the production of hydrocarbons ofsuperior values and largely in the aromatic series, such as benzene and toluene. Relatively high-boling products, such as naphthalene and anthracene, which are solids at ordinary temperature, are also produced, together withV non-condensible gases comprising hydrogen, methane and parafllnic and olemc hydrocarbons. Y

By adjusting the rate of downward travel of the filling material M, and by controlling the temperature conditionsin the din'erent parts of the retort I0, oil of widely varying characteristics may be successfully cracked. Extended experiments have shown that the low-priced oil, such as Bunker C oil having a gravity of 12 A. P. I. or less, may be cracked to advantage, as

it not only yields excellent oil gas and valuable 1 aromatics, but also a large amount of carbon to be utilized in making water gas which is im meaiately enriched by aamixture of the ou gas higher thanwith the usual intermittent process,

in which the principal by-product is a heavy, viscous and low-priced water gas tar. The byproducts of our process, on the other hand, are suitable `for the production of more valuable products such as blending agents, solvents,` wetting agents and lubricants. y

In the production of carbureted water gas by the usual intermittent process, further lowering.

lof the net production cost depends chiefly on y reducing the cost of the raw materials used, while our improved process are the low-grade oil introduced through the pipe 34 and the steam in. troduced through the pipe 40 or the pipe 44.

The chemical composition and properties of the by-products produced by our improved process are modified by the temperature maintained in the cracking zone, by the length oftime the oil vapors remainin the cracking zone, and by the chemical compositionv of the cracking oil. Changes in the composition of the retort wall and in the retort filling material may also have important effects on the nature of the byproducts.

The control and maintenance of uniform temperature conditions in our improved process are particularly important, as some 90% of the byproduct credits in money value, comprise oils having a boiling range between 100 F. and '700 l". Such oils cannot be produced in substantial amounts and of uniform quality under the widely varying temperature conditions of the intermittent water gas processes.

While we have described our improved process.

as being adapted to produce commercial gas having the usual standard heating values, our process is very flexible and may be used to advan- -tage in producing other grades of gas if so desired. If a lighter gas oil is substituted for the assenso unchanged Aunder the described conditions of operation.

The words "upright retort" as used in the claims are intended to denne a retort so positioned that the solid refractory material charged to the retort will 'move downward therein by gravity.

The term ,water gas as used in this specification and in th following claims is intended to dene a combustible gaseous mixture produced by the reaction of steam on highly heated carbon, and consisting essentially of hydrogen and carbon-monoxide, both in substantial proportions.

Having thus described our invention and the advantages thereof, we do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what we claim is: l. 'I'he vcontinuous process for making carbureted water gas in a retort, using oil and steam as the initial reacting materials and relying pri-f which carbon is deposited in and on said refractory material, progressively moving said heated refractory material and the carbon deposited thereondownwardly through said retort, contin. uously reacting on a portion at lel t Iof said deposited carbon by steam admit W water-gas-producin'g zone in said retort, continuously passing the resultingwater gas upwardly foot may easily be produced. 0n the other hand,

by a different modification of conditions, fuel gas of relatively low heating value may be produced for industrial purposes; In each case. by-prod- -ucts rich in aromatic hydrocarbons will be produced, and the net production cost of manufacture will be correspondingly low.

The rates of feed of the charging-device 21 and of the discharging device 3| are so adjusted relative to the oil feed, that the deposited carbon will be removed fast enough to prevent clogging The words refractory material as used in the claims are intended to designate such materials as coke, calcined clay, broken re brickchromite, bauxite, etc. which are infusible and chemically through the refractory material in the retort andl mixing said water gas with the oil gas and va pors'formed in the cracking zone to form a carb ureted water gas of increased heating value, progressively removing lsaid carbureted water gas, oil vapors and any excess steam from the upper part of said retort, and progressively discharging the refractory material and any unreacted carbon from the lower end'of the retort.

2. 'Ihe continuous process for making carbureted water gas lin a retort using ,oil and steam as the initial reacting materials and relying primarily on external heat for bringing about the gas-making reactions, which comprisesfeeding fragmentary solid refractory material which does not enter actively into the gas-making reactionsv to the upper part of an upright retort, externally and continuously heating said retort and said refractory material, progressively admitting oil to the heated refractory material and cracking said oil in an'oil-cracking zone in said retort, therebyproducing oil gas and vapors and oil carbon, which carbon is deposited in and on said refractory material, progressively moving said heated refractory material and the carbon deposited thereon downwardly by gravity through said retort, continuously reacting on a portion at least of said deposited carbon in a lower water-gasproducing zone in said retort by steam admitted to said retort, continuously passing the resulting water gas upwardly through the refractory material in the .retort and mixing said water gas with the oil gas and vapors formed in the oilcracking zone to form a carbureted water gas of increased heating value, progressively removing -said carbureted water gas, oil vapors and any to' a lower reactions, which comprises progressively feeding fragmentary solid refractory material which does not enter actively into the gas-making reactions l to the upper part of an upright retort, externally and continuously heating said retort and the refractory material in said retort, progressively feeding oil to the heated refractory material and cracking said oil in an oil-cracking zone in said retort at a substantially uniformselected temperature in the temperature range between 1200" F. and 1600 F., thereby producing oil gas, oil vapors containing a large proportion of aromatic hydrocarbons, and oil carbon which is deposited in and on said refractory material, separately controlling the oil feed, progressively moving said heated refractory material and the carbon deposited thereon downwardly through said retort,

continuously reacting on a portion at least of said deposited carbon by steam admitted thereto in a lower water-gas-producing zone, continuously passing the resulting water gas upwardly through the refractory material in the-retort and mixing said water gas with the oil gas and vapors formed in the cracking zone to form a carbureted water gas of increased heating value, progressively removing said carbureted water gas, oil vapors and any excess steam from the upper part of said retort, progressively discharging the refractory material andthe unreacted carbon from the lower end of the retort," and coordinating the rate of feed of refractory material to the top of the retort with the rate of discharge of the refractory material and unreacted carbon from end of' the retort. V

4. The continuous process of manufacturing carbureted water gas in a retort, using oil and steam as the initial reacting materials and relying primarily on external heat for bringing about the gas-making reactions, which comprises passing fragmentary solid refractory material which does not enter actively into the gas-making reactions axially downwardly by gravityvthrough an elongated vertical retort, selectively and externally heating different horizontal zones of -said retort andthe refractory material therein toV an upper oil-cracking zone in said retort and in the presence of water gas, thereby producing oil gas and oil vapors and carbon, which carbon is deposited in and on said refractory material, said .carbon and said refractory material being progre'ssively transferred by gravity from the' cracking zone to a lower water-gas zone in said retort',

continuously supplying steam in said water-gas zone toreact with at least a partof said depomted carbon to produce lwater gas, enriching said water-gas with oil gas and vapors formed in the'oil cracking zone to form a carbureted' water gas, progressively removing said enriched the lower 4 essaies water gas, oil vapors and any excess steam from the upper end of said retort, and highly Aheating said steam when admitted to the retort by heat recovered from the refractory material and the unreacted carbon remaining thereon before said latter elements are discharged from said retort, thereby conserving recoverable heat therefrom.

5. The continuous process of making carbureted water gas and hydrocarbon products which are predominantly aromatic in character, in a retort and relying primarily on external heat for bringing about the gas-making reactions, which consists in continuously cracking petroleum oil at substantially atmospheric pressure and at relatively high temperature and in an atmosphere of heated water gas in a retort filled with a moving mass of solid fragmentary refractory material which does not enter actively into the gas-making reactions, thereby producing oil gas and oil vapors containing a large proportion of aromatic hydrocarbons, externally and continuouslyheating said retort and the refractory material therein, depositing the carbon produced by cracking the oil in and on said refractory. material, transferring said heated material and said deposited carbon by gravity to a lower watergas zone insaid retort, continuously supplying steam to react with a part `of -said carbon to and any excess steam from the retort and recovering the predominant aromatic hydrocar` -bons from the gaseous mixture, and removing the refractory material and the unreacted carbon from the lower end-of said retort.

6. The continuous process for converting essentially non-aromatic fluid hydrocarbons into gases which are substantially oleilnic and liquids which are predominantly aromatic and olenic and solidswhich are aromatic, which consists in cracking the said essentially non-aromatic fluid hydrocarbons at substantially atmospheric pressure and in an atmosphere essentially containing highly heated steam and water gas' by introducing the uid hydrocarbon into a retort primarily externally heated and through which a mass of solid fragmentary heated refractory material is moving downward and the said highly heated steam and water gas are moving upward, cracking the uid hydrocarbon to oil gas, vapors and oil carbon, depositing the carbon as it is formed in the cracking operation in and on the mass of refractory material, progressivelyremoving the refractory-material with4 the deposited carbon downward from the cracking zone and into a lower zone where water gas is made by reactingv on the deposited carbon with steam admitted at the bottom -of the retort. said steam also cooling the refractory material and the carbon deposited therein and thereby conserving he'at. causing said water gas, and steam which has been highly superheated in the water gas zone, to now up through the retort to the crack-- ing zone, said water gas and any excess steam thereafter-passing out of the top of the retort mixed with the predominantly aromatic and oleflnic oil gases and vapors, and from which mixture aromatic and oleilnic products are subsequently recovered by conventional methods of into the cracking reaction :to the upper end of '3.

retort, externally and continuously heating said retort and the refractory material therein sufficiently to bring about an oil-cracking reaction at a relatively high temperature and substantially at atmospheric pressure, feeding said nonaromatic fluid hydrocarbons to said retort and continuously vaporizing and cracking the sameA in contact with the heated refractory material in a cracking zone in said retort, thereby producing oil gas and vapors and carbon which is deposited in and on said refractory material, progressively transferring the deposited carbon with said refractory material from the cracking zone to a lower water-gas zone in said retort, continuously supplying heated aqueous iiuid in said water-gas zone to react with a part of said deposited carbon fractory material is movingdownward and the said water gas and condensable vapors are moving upward, depositing carbon as it is formed in the cracking operation in the mass of refractory material, progressively removing the refractory material and the deposited carbon downward from the cracking zone into a lower zone where water gas is made by reacting on the deposited carbon with steam admitted near the bottom of the retort, causing said water gas to flow up 'through the retort to the cracking zone, said Water gas andthe volatile products of the oilcracking operation passing out of the retort, and removing the refractory material and the carbon contained therein from the bottom of the retort.

9. A continuous process for converting essentially non-aromatic 'uid hydrocarbon mixtures into gases of high caloric value which are rich in. olenic hydrocarbons and to liquids predominantly ,aromatic and olenic in' character, which consists crackingthe s aid hydrocarbon mixto produce water gas, passing said water gas vup 'through the cracking zone and mixing said water gas with -said oil gas and vapors, discharging said refractory material and the unreacted carbon from the lower end ofsaid'retort, progressively ture in an atmosphere of highly-heatedl water.

gas' in a retort primarily externally heated and through which a mass of solid, fragmentary, re-

fractory material is movlngfrom the entrance f.

end toward the discharge end of said retort and the said water gas and condensable vapors are `zone nearer the discharge end of the retort and where water gas is made by reacting on the deposited carbon with steam admitted near the discharge end of the retort, causing lsaid water gas to ow through the retort from the water gas -zone to the cracking zone, said watergas and the volatile products of the oil-cracking operation thereafter passing lout of the retort near the entrance end thereof, and. removing the refractory -materialvahd the carbon deposited thereon from the discharge end of the retort.

ROLLIN M. CHATTERTON. PETER F. PAFFEN. 

